1. Field of the Invention
This invention concerns a hermetic rotary compressor for an air conditioning application. In particular, this invention relates to resonator for a hermetic rotary compressor capable of a certain extent of noise reduction.
2. Description of the Prior Art
The best method of noise reduction in compressors lies in dealing with the source of noise, i.e., in reducing high frequency components of gas pulsation.
In the past, means such as mufflers, Helmholtz resonators, and orifices have been used for noise reduction. Mufflers and orifices are inherently restricted to be designed into rotary compressor components because of large physical dimension which is normally required for adequate noise reduction.
Compared to those, a resonator can provide physical design parameters which are adequate for reducing gas pulsation. However, designing a resonator with target center frequency and frequency band with certain magnitude of desired noise reduction is also geometrically restricted in many ways to be installed into a limited space in compressor. A resonator is composed of a chamber and an entrance channel connected thereto. The channel communicates the resonator chamber and compression chamber. A medium in the entrance channel acts as a mass, while that in the chamber acts as a spring. Thus, the volume of the chamber and the cross-sectional area and length of the entrance channel are parameters which determine target center frequency and frequency band with certain magnitude of desired noise reduction.
Increasing volume of resonator increases frequency band with certain magnitude of desired noise reduction, thereby resulting in an increase in noise reduction. Thus, a need to maximize frequency band with certain noise reduction effect while minimizing efficiency penalty arises.
Therefore, a method of designing a resonator of adequate configuration which is not restricted in geometry while providing desired target center frequency and frequency band with certain magnitude of desired noise reduction has been in demand and desirable.